Current mass production automobile coatings consist for the most part of a base lacquer/clear lacquer covering coating which is applied to a body which has been electrophoretically primed and coated with primer surfacer. In the course of this procedure, the base lacquer and the clear lacquer are preferably applied wet-into-wet, i.e. after a ventilation period, optionally with heating, and after the subsequent application of a clear lacquer, the base lacquer is stoved jointly with the latter. Processes which serve to reduce further stoving steps have also become known, in which the electrophoretically deposited primer coat and the primer surfacer coat are applied by the wet-into-wet method, as described in DE-A-41 26 476 or EP-A-0 595 186 for example. The primer surfacer coats have to be applied to give a dry film thickness of 30 .mu.m or more, which is customary for primer surfacer lacquers.
The procedure according to DE-A-41 26 476 and EP-A-0 595 186 is subject to restrictions as regards the composition of the primer surfacer coats which are applied wet-into-wet, i.e. it is not possible to use any desired primer surfacer coating media. Furthermore, the properties of the electro-dip lacquer material and of the primer surfacer material have to be matched to each other.
It is known from EP-A-0 265 363 that a previously stoved, cataphoretically deposited primer coat can be provided with a two-coat base lacquer/clear lacquer covering coat by the wet-into-wet method. The primer surfacer coat is dispensed with. An effect which is problematical, however, is that stone impact damage to motor vehicles coated by this process is particularly conspicuous, since on stone impact the primer coat is exposed due to the debonding of the covering lacquer. Whilst protection from corrosion is still in fact ensured, the visual impression cannot be tolerated, however.
For reasons of rationalisation and savings in material, there is a desire for a reduction in the coating thickness of the lacquer structure for the coating of motor vehicles, but without this resulting in significant losses in the overall level of properties thereof.